1. Field of the Invention
The present invention is directed to methods of treating a patient suffering from one or more types of cognitive disorders using 1-benzyl-1-hydroxy-2,3-diamino-propyl amines, 3-benzyl-3-hydroxy-2-amino-propionic acid amides and related compounds.
2. Background of the Invention
1-Phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP) was discovered by Vunam, R. R. and Radin, N., Chem. Phys. Lipids, 26, 265-278, 1980. Preparation of PDMP is described in Inokuchi, J. et al., J. Lipid Res. 28, 565-571, 1987; Radin, A. et al., NeuroProtocols, 3(2), 145-55, 1993; Abe et al., J. Lipid Res. 36, 611-621, 1995 and U.S. Pat. No. 5,916,911.
The isomers most active have the R,R-(D-threo)-configuration.

Preparation of enantiomerically pure D-threo-PDMP has been reported by Mitchell, Scott A. [J. Org. Chem., 63 (24), 8837-8842, 1998]; Miura, T. et al, [Bioorg. Med. Chem., 6, 1481-1498, 1998]; Shin, S. et al., [Tetrahedron asymmetry, 11, 3293-3301, 2000]; WO 2002012185
A stereoselective synthesis of enantiomerically pure D-threo-PDMP has also been described by Shin, S. et al., Tetrahedron asymmetry, 11, 3293-3301, 2000 and WO 2002012185 the key step is the regioselective cleavage by nitrogen nucleophiles, as morpholine, of the C(3)-N-bond of non-activated enantiomerically pure aziridine-2-methanols.
On the other hand, the synthesis of enantiomerically pure (1S,2S)-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (L-threo-PDMP) from L-serine has also been described by Mitchell, Scott A., J. Org. Chem., 63 (24), 8837-8842, 1998.
Other known methods to obtain L-threo-PDMP are described by Miura, T. et al, Bioorg. Med. Chem., 6, 1481-1498, 1998 and in JP-A-9-216858.
Synthesis of (1S,2S)-threo- and (1R,2S)-erythro-1-phenyl-2-palmitoylamino-3-N-morpholino-1-propanol (PPMP) were described starting from Garner aldehyde of L-serine, by Nishida, A., Synlett, 4, 389-390, 1998.

D-threo-1-phenyl-2-palmitoylamino-3-pyrrolidino-1-propanol (P4 or PPPP) analogues were first obtained by a Mannich reaction as described Abe, A. et al., J. Biochem., 111, 191-196, 1992 or U.S. Pat. No. 5,916,911 and WO 2001004108.
Preparation of D-threo-4′-hydroxy-P4, was described by Lee, L. et al., J. Biol. Chem., 274, 21, 14662-14669, 1999. In addition, a series of dioxane substitutions was designed and tested. These included 3′,4′-methylenedioxyphenyl-3′,4′-ethylenedioxyphenyl-, and 3′,4′-trimethylenedioxyphenyl-substituted homologues.
Synthesis of enantiomerically pure D-threo-1-phenyl-2-benzyloxycarbonylamino-3-pyrrolidino-1-propanol (PBPP) and D-threo-P4 and its analogues from N-benzyloxycarbonyl-D-serine, was described by Jimbo M. et al, J. Biochem., 127(3), 485-91, 2000 and EP 782992 (Seikagaku Kogyo Co.).

Novel prodrugs of P4 derivatives were described in US 20020198240 and WO 2002062777.
Synthesis of enantiomerically pure of D-threo-ethylenedioxy-P4 and D-threo-p-methoxy-P4 were described by Husain A. and Ganem B., Tetrahedron Lett., 43, 8621-8623, 2002. The key step is a highly syn-selective additions of aryl Grignard reagents to Garner aldehyde.

Diastereoselective synthesis of P4 analogues were described in U.S. Ser. No. 03/015,3768 and WO 2003045928 (Genzyme Corp.); Oxazolines I [R1=(un)substituted aryl; R2, R3=H, (un)substituted aliphatic; NR2R3=heterocyclic] are prepared as intermediates for P4 glucosyltransferase inhibitors from R1CHO and R2R3NCOCH2CN. Thus, methyl isocyanoacetate CNCH2CO2Me was treated with pyrrolidine and the amide was treated with 1,4-benzodioxane-6-carboxaldehyde, followed by hydrolysis of the oxazoline using HCl in methanol, reduction of the keto group of amide II using LiAlH4, and acylation with palmitoyl chloride to give D,L-threo-ethylenedioxy-P4 III.
Synthesis of enantiopure P4 analogues were described in WO 2003008399 (Genzyme Corp.).
P4 derivatives, such as I [R1, R5=un(substituted) aromatic; R2, R3=H, un(substituted) aliphatic; NR2R3=(un)substituted non-aromatic heterocyclic ring; R4=O, H2], have been prepared. D-threo-ethylenedioxy-P4 has been prepared via a multistep synthetic sequence starting from S-(+)-Ph glycinol, phenyl-α-bromoacetate, 1,4-benzodioxan-6-carboxaldehyde, pyrrolidine and palmitoyl chloride.

New D-threo-P4 analogues that bear ether substituents on the aromatic ring have been recently synthesized. Slavish et al., Bioorg. Med. Chem. Lett., 14, 1487-1490, 2004.
Further references which serve as background to the present invention are U.S. Pat. Nos. 5,945,442; 5,952,370; 6,030,995 and 6,051,598; Journal of Labelled Compounds & Radiopharmaceuticals (1996), 38(3), 285-97; Published PCT application WO 01/38228; and Kastron et al. Latvijas P S R Zinatnu Akademijas Vestis, Kimijas Serija (1965) (4), 474-7.